Mounting mechanism for rotative aircraft sustaining wings



Feb. 9, 1937.

J. s. PECKER'EI' AL v MOUNTING MECHANISM FOR ROTATIVE AIRCRAFT SUSTAINING WINGS Original Filed Aug. 31,1951 3 Sheets-Sheet l WINGS Feb. 9, 1937. J. 5. PECKER ET AL MOUNTING MECHANISM FOR ROTATIVE AIRCRAFT SUSTAINING Original Filed Aug. 31, 1931 3 Sheets-Sheet 2 WA??? w ll AT EYS Feb. 9, 1937. J. '5. PECKER E'IAL MOUNTING MECHANISM FOR ROTATIVE AIRCRAFT SUSTAINING WINGS Original Filed Aug. 31, 1931 3 Sheets-Sheet 3 III.

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I? RS WW NEYS .Figure 1, are substantially as follows.

Patented Feb. 9, 1937 2,069,846 MOUNTING MECHANISM FOR nom'rrva I AIRCRAFT SUSTAINING Philadelphia, and Agnew E.

Joseph S. Pecker,

WINGS Larsen, Huntingdon Valley, Pa, asslgnors to Autogiro Company of America,

Willow Grove,

lPa., a corporation of Delaware Original 2 Claims.

This invention relates to improvements in mounting mechanism for rotative aircraft sustaining wings, and the invention is especially concerned with rotative wings normally adapted to be driven by relative air-flow in flight and having pivot joints for attaching the wings to a central hub structure so as to permit freedom for force compensating movements under the influence of variations in flight forces.

More specifically, some of the important features of the invention are involved in the use of cooperating wing pivot parts so arranged as to maintain the total size and weight of the parts at a minimum and even permit substantial reduction in such size and weight for a given size craft. Another important object relates to an efiective and simple lubrication means for the articulations or pivots for the wings. Still further, the invention contemplates an improved mechanism for controlling movements of the wings about their pivots.

In addition to all the foregoing, the arrangement of the several parts, as will appear more fully as this description proceeds, is such as to aiford adequate strength and minimum air resistance and, further, to cooperate neatly with other parts of a rotor hub or head assembly, so

as to provide a compact and relatively small sized hub unit.

Other objects and advantages will appear more fully after a consideration of the accompanying drawings, illustrating a preferred embodiment of the invention, in which- Figure l is a somewhat diagrammatic side elevational view of an aircraft of the rotative sustaining wing type, with the improvements of the present invention applied thereto;

Figure 2 is a vertical sectional view through the rotor head assembly and certain of the associated blade or wing pivot arrangements, which parts are constructed in accordance with this invention;

Figure 3 is a top view, partly in elevation and partly in horizontal section, of portions of the mechanism shown in Figure 2; and

Figure 4 is an enlarged detail view of a pivot part preferably employed.

Before considering the drawings, attention is directed to the fact that the present application is a division of our copending application Serial No. 560,314, filed August 31, 1931, now Patent No. 2,017,105, issued October 15, 1935.

The general features of the craft, as shown in The fuselage is designated by the numeral 5, and the application August 31, 1931,

Divided and 1934, Serial No. 724,470

Serial No.

this application May 8,

side view of Figure 1 also includes a showing of an engine 6 driving propeller I, an empennage structure 8 and landing gear 9.

The sustaining rotor, comprising a plurality of blades I0, is mounted above the body of the craft in any suitable manner as by means of the pylon posts ll joined at their upper ends in an apex member I2, which serves more or less directly to support the hub structure generally indicated at i3. The blades or wings II] are pivoted or articulated to the hub structure on two difierent axes l4 and IS, the first of which extends generally horizontally and the latter of which extends in an upright direction. Blade supporting members, such as cables I 6, may be employed in order to restrain the blades as against excessive downward swinging movement when they are at rest or not rotating at flight speeds. The general arrangements of the craft may also include a mech anism for initiating rotation of the rotor prior to take-01f from the ground and, for this purpose, in Figure 1 a drive shaft I1 is shown extended upwardly from the engine to the rotor hub.

The various features of the rotor head or hub construction, including the blade articulations or pivots, will appear to better advantage from inspection of Figures 2 and 3. In these views, the rotor head support at the top of the pylon is shown at 12. The member I! has a central aperture or socket adapted to receive the spindle l8, and this spindle is extneded upwardly somewhat above the member l2 so as to provide a support for the hub member proper 19. The hub member surrounds the spindle and radial and thrust bearings 20 are inserted therebetween to ensure free operation. A top cone-shaped element 2| is secured to the hub member 19 and at its upper end is equipped with a fitting having apertured lugs 22 serving as attachment means for the blade supporting cables or the like I 6 shown in Figure 1.

At its lower end the central spindle l8 may be provided with a flanged nut 23 threaded internally of the spindle and adapted to engage the lower side of the support l2 so as to transmit the thrust of sustension of the craft from the hub and its bearings, through the spindle I8 to the fixed support I 2 and from there through the pylon supporting elements II to the body of the craft.

The rotor head assembly may also include a drum-like structure 24 secured to the hub member l9 toward the lower end thereof and adapted to cooperate with a brake mechanism generally indicated at 25, which may be employed to retard 1'0- connection with v31 being provided for ment of this joint, therefore, takes place between tation of the rotor after a landing has been made.

Additionally, the starter mechanism, including the of the casing 20, rotates during rotor operation.

The two casing parts together constitute an effective means for preventing entrance of moisture, dirt or the like.

For the purposes of attaching the wings or blades to the hub member I3, this member carries pairs of opposed and apertured lugs 30 which, in the embodiment shown, are disposed in such mannerthat the lugs of opposite pairs are arranged substantially in alignment with each other and substantially tangentially to the hub It. This lu! arrangement, as will be seen in Figure 2, results in the disposition of at least a portion of the several lugs adjacent to the internal hub reenforcements Isa-Illa, which is of importance for structural reasons, especially effective distribution and transmission of flight forces and thrusts through the hub member and spindle.

The structure employed for the attachment of the blades or wings to the hub will further be seen to include a root end fitting or the like 31 which is provided with a forked end 32-32, each portion of the fork being 'apertured to receive the pivot member 33. The parts 32-32 embrace an additional joint part 34 which is also apertured to receive the pin or pivot part 33. These parts are those which are embodied or incorporated in the pivot structure indicated generally and somewhat diagrammatically by the numeral i5 in Figure 1.

In accordance with this invention, the pivot member 33 is fixedly mounted within the fork 32-32, cap members 35-35, tie bolt 35 and pin this purpose. The moveits bearings to the central the member 32 and the pivot 33 and, if desired, bearing bushings 38 may be interposed between these relatively movable joint parts.

By constructing the bearing may be distributed overrelatively extensive bearing surfaces. This is advantageous, of course, in reducing wear as well as in permitting reduction in the width and weight of the forked 55 parts Another feature of considerable importance in the blade articulation just de scribed is involved in the arrangement of the pivot pin 33 as a lubricant reservoir. This reservoir is preferably of such capacity as to contain a charge of grease suflicient to lubricate the hearing surfaces associated with the pin 33 from the time of one general rotor inspection to another. A convenient fitting, in the natiu'e of a one-way valve 39, may be disposed in one of the cap members 35, so that charged by the application of a pressure gun. The lubricant'is fed from the interior of the pin 33 to the bearing surfaces at the outer cylindrical wall of this pin through ducts 40 and grooves 4| (see Figure 4). As seen in this figure, as well as in Figure 2, the grooves H are extended within the high pressure area incident to the action of centrifugal force during rotation of the rotor. In addition, the distributing grooves are joint 32, 33 and 34 in the manner just described, the load imposed upon the the reservoir may readily be preferably extended about the pin 33 throughout an are preferably approximately equal to that defined by the limits of blade swinging movements under the influence of normal irregularities in flight forces. In this way, highest pressure is always effectively supplied with lubricant. It is further to be observed that the arrangement of the pin 34 and the immediately cooperating members is such that the lubricant will be fed from the reservoir, to the high pressure area, under the influence of centrifugal force. This, of course, is also of considerable importance since it provides a very constant and eilective feedof the lubricant.

In order to provide for control of certain blade movements about the pivots 33, the blade root 3i and the joint part 42, for each blade, may con-' veniently be provided with opposed bracket members 43 and 44 at each side of the axis of this joint. A resilient, device, such as the rubber block 45, may be inserted between the opposed brackets of each pair in'the manner clearly shown in Figure 3. Preferably, the brackets and the resilient blocks are so constructed as to normally maintain the blocks under at least a slight compression, and these blocks will therefore yieldingly resist any relative angular movement of the blade root 3i and the joint part 42.

From inspectionof Figures 2 and 3, it'will be seen that the joint part 42 is rigid with the member 34 which isapertured to receive pin 33 and, further, that the part 42 is cylindrical and internally threaded to cooperate with an externally threaded member. The members 42 and 40, therefore, may be employed as a means of adjustment of the incidence of the individual wings,

the action of such an arrangement being more fully described and illustrated in the copending application of Joseph S. Pecker, Serial No. 567,343,

filed October 17th, 1931, now Patent No. 1,995,460,

issued March 26, 1935. .Since this incidence adjustment mechanism forms no part of the present invention per se, no detailed description, thereof is included herein.

Toward its inner end, the member 45 is provided with a transverse aperture through which the pivot 41 is extended. This pivot serves to connect a blade with a pair of apertured lugs 30-30 of the hub 13 and the parts may be retained in their proper operative positions by means of'cap members 48-40, tie bolt 43 and the set screw 50. As will beapparent from comparison of Figures 1, 2 and 3, the joint structure 45, 41 and 30-30 serves tov pivot a blade to the hub structure on a substantially horizontally extended axis as diagrammatically indicated at 14 in Fig. 1.

Similarly to the pin 33, the pin 41 is also formed as a reservoir for grease'which may be fed throughducts or passages 5i and grooves 52 to the bearing surfaces between the bushings 53 and the outer 00 surface'of the pin 41. A pressure gun fitting 34 may also be provided in one of the cap members 40. The set screw 50 serves to fixedly position the pin 41 with respect to the joint part 40, so that the grease grooves 52 will beretained in the high a:

the zone or area of 5 the ground or in flight, cushion abnormal upward movements of the blades which may be caused, for example, by gusts of wind when the rotor is standing idle when the ship is on the ground. At this point it is also to be observed that the full line showing of the blade root in Figure 2 illustrates the lower limit of movement on the horizontal articulation 47. Thus, while relatively great freedom for upward and downward swinging movement is provided, the various parts of the blade articulations and the adjacent devices associated with the rotor hub, such as the brake and starter, are arranged in a relatively comp-act manner. Note that the positioning of the pivots 33 and 41 is such that the starter pinion 26 lies between the two pivots. This is of importance in obtaining the necessary clearances while at the same time providing for the mounting of the blades and starter parts in horizontal planes which are quite close to each other.

The structure above described is advantageous, in general, since all the various parts (including the main rotor bearings, the blade pivot lugs and pivot joints, the brake parts and associated rotor driving mechanism), are all relatively arranged so as to produce a much more compact rotor head structure than obtained heretofore. This, of course, reduces parasite drag, head resistance and skin friction to a minimum and, it should be observed that, in addition to the foregoing, very great strength is provided even though the parts, for a machine of given size, are relatively small and light in weight.

Still further, the relatively wide spacing of the blade attaching lugs 3030 permits relatively light construction thereof, since by increasing the resisting moment arm the strains and thrusts of operation (especially during blade swinging movements) which are transmitted to the hub, are materially reduced.

Various of the individual blade pivot joints, furthermore, are also arranged advantageously to distribute bearing loads over relatively large bearing surfaces. The size and weight of these parts, therefore, may also be reduced in a structure adapted for use in connection with a craft of given size.

A novel and highly desirable type of lubrication for the blade articulations is also provided, it being particularly advantageous in permitting convenient renewal of the lubricant at the pe-' riodic times of rotor head inspection and lubrication. The lubrication arrangement is also of advantage as it provides for automatic feed, under the action of centrifugal force, to the high pressure areas of both the horizontal as well as the vertical pins.

appearance.

We claim of, the diagonal extension being sufiicient to traverse an arc approximating that defined by blade swinging movements during normal flight operation, the groove being located in the high pressure area of the pin set up as a result of the action of centrifugal force incident to rotation of the rotor, and said groove serving to deliver and distribute lubricant from the interior of the pin to said high pressure area under the infiuence of said centrifugal force.

2. In an aircraft sustaining rotor of the pivoted blade type, a mounting structure for the blades with apertured lug means, link means for attaching a blade to the mounting structure, a lubricant-containing pivot pin fixedly mounted in the link means and rotatively mounted in a lug aperture and providing movement of the blade transverse the plane of rotation, additional apertured lug means at the blade root, a similar lubricant-containing pivot pin rotatively mounted in the link means and fixed in the lug means of the blade providing for movement of the blade in the plane of rotation, each pivot pin having a groove extending generally axially and diagonally of the pin and being in communication with the interior thereof, the diagonal extension being suflicient to traverse an arc approximating that defined by blade swinging movements during normal flight operation, the groove being located in the high pressure area of the pin set up as a result of the action of centrifugal force incident to rotation of the rotor, said grooves serving to deliver and distribute lubricant from the interior of the pins to the high pressure areas thereof under the influence of said centrifugal force.

JOSEPH S. PECKER. AGNEW E. LARSEN. 

